1. Field of the Invention
The present invention relates to an electric rotating machine and electric vehicle whose output characteristics can be freely adjusted.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. HEI 9-37598 relates to a control apparatus of a generator for a vehicle. In this invention, a radial gap motor is provided with an axial direction displacement mechanism that adjusts the gap between the stator and rotor. This axial direction displacement mechanism has a solenoid, and when the solenoid is excited, generation characteristics are changed by adjusting the gap between the rotor and stator by displacement in an axial direction.
However, according Japanese Patent Application Laid-Open No. HEI 9-37598, precise control is not possible since the rotor is displaced by a solenoid. Consequently, it is difficult to apply this invention to the motor of an electric vehicle, which requires precise control according to the driving force and vehicle speed. Also, as a sample implementation of the invention of Japanese Patent Application Laid-Open No. HEI 9-37598, an example is shown in which the stator is moved by a motor and screw, but with this configuration it is not possible to move a rotating rotor.
Thus, as a generator for a vehicle, it is desirable to use an axial gap motor that can be made cheaper and thinner than the radial gap motor used in Patent Document 1, and, with regard to gap adjustment, has more notable changes in generation characteristics than the radial gap motor.
The technology disclosed in Japanese Patent Publication No. 2749560, for example, is known as a technology for adjusting the gap between the stator teeth and the rotor magnet in an axial gap motor.
FIG. 1 is a principal-part cross-sectional diagram showing a conventional gap adjustable motor disclosed in Japanese Patent Publication No. 2749560.
In the motor shown in FIG. 1, aperture 4 is formed in the center part of the top surface of drum securing section 3 that incorporates rotating drum 2, and motor stator 5 that has a coil is located around this aperture 4.
Magnet 6 is located facing this motor stator 5, and this magnet 6 is attached to motor rotor 7 located above drum securing section 3.
Motor rotor 7 is connected to rotating drum 2 via fastening and adjustment member 8 located in aperture 4 of drum securing section 3.
Fastening and adjustment member 8 is a screw-shaped element with an externally threaded section formed on tip section 9, that is inserted into motor rotor 7 from above, and whose head 10 is locked on the top surface of motor rotor 7.
Shaft section 11 is passed through by motor rotor 7 and compression spring 12, and tip section 9 is screwed into a tapped (internally threaded) groove on the top surface of rotating drum 2. Compression spring 12 is located between motor rotor 7 and rotating drum 2, and applies force in a direction such that the top surface of rotating drum 2 and motor rotor 7 are moved apart.
According to this configuration, when fastening and adjustment member 8 is loosened by manipulation of head 10 of fastening and adjustment member 8, motor rotor 7 and rotating drum 2 are relatively moved apart by the restoring force of compression spring 12. As a result, gap G between magnet 6 of motor rotor 7 and motor stator 5 increases. Also, when fastening and adjustment member 8 is tightened, bush 13 and rotating drum 2 become relatively closer, and thus gap G decreases.